This application is based upon provisional 60/050,857 filed Jun. 26, 1997.
The present invention relates to a method of applying a predetermined pattern onto a support means of a sign, which pattern is to form the decoration and/or information on the sign, utilising a foil comprising a pattern layer and a carrier layer with an adhesive layer uniting them, wherein parts to be included in said pattern are cut out in the pattern layer of the foil by means of a cutting device which is controlled by an electronic control unit that is pre-programmed in accordance with the predetermined pattern, after which the foil is placed on a laminating table having a flat laying-out surface in an application device with the pattern layer facing upwards.
The invention also relates to a device for applying a predetermined pattern onto a support means of a sign, which pattern is to form the decoration and/or information on the sign, utilising a foil comprising a pattern layer and a carrier layer with an adhesive layer uniting them, wherein parts to be included in said pattern are cut out in the pattern layer of the foil by means of a cutting device which is controlled by an electronic control unit that is pre-programmed in accordance with the predetermined pattern, said device comprising a laminating table having a flat laying-out surface on which the foil is placed with the pattern layer facing upwards.
A traditional stretch-fabric sign generally consists of a stand with a pair of parallel support elements anchored in said stand, a support means in the form of a flexible stretch-fabric extending in a plane between said support elements, and some form of attachment means to secure the stretch-fabric to the support elements. Two parallel edge portions of the fabric are folded around a strip enabling the edges of the fabric to be detachably connected to the support elements through said attachment means. The stretch-fabric, intended to carry and expose information, particularly advertisements, by means of one or more self-adhesive lengths of the pattern layer of a decorative foil, also known as decor film, being applied on the sign surface of the stretch-fabric, is suitably manufactured from some weatherproof, durable material such as plastic sheeting. The lengths of decor film are produced by cutting out a desired pattern in the form of information, e.g. text, or decoration, e.g. graphics, in the upper layer of said decor foil consisting of said decor film with a thin adhesive layer facing a second layer, the backing, normally consisting of a waxed paper, without the waxed paper beneath being perforated. Cutting is effected by a foil cutter when the desired pattern has first been either entered into or created in an electronic control unit, usually a computer connected to the foil cutter. The decor foil cut in this way is then placed on a table, together with the stretch-fabric. A transfer film with a self-adhesive, non-permanent layer of adhesive on one surface of the transfer film is applied over the entire surface of the pattern layer so that a laminate is formed consisting of the foil and the transfer film. Said transfer film is generally rolled up with the adhesive layer facing in towards the centre of the roll so that the outside of the roll is always free from adhesive. The wax paper of the foil is then removed so that the permanent adhesive surface of the pattern layer is exposed either by removing all the wax paper at once, as is the case if the pattern to be applied covers only a small surface, or, in the case of larger pattern areas, by the permanent adhesive surface being gradually exposed as the pattern layer is applied on the surface of the support means. During removal of the wax paper the cut-out parts of the pattern layer which are to form the desired pattern are pressed out manually from said foil using a hand tool, e.g. a spatula, so that they adhere to the surface of the transfer film. The parts of the pattern layer not forming the desired pattern will thus remain on the waxed paper and are discarded together with the paper. When the wax paper has been entirely or partially removed in the manner described above, a short length of the pattern layer adhered to the transfer film is applied on the surface of the support means, i.e. the stretch-fabric, application being performed with the aid of the spatula, while new strips of adhesive surface are applied, at the same time smoothing the whole with the spatula. When the entire pattern layer has been applied the transfer film is finally removed from the now decorated stretch-fabric.
If the finished sign is to consist of several fields of different colours, each colour must be cut out in a separate foil and then each foil must be applied individually, one after the other on the stretch-fabric. First securing and then smoothing out all the components in the sign under production has hitherto entailed extremely complicated and laborious processes. Furthermore, the less than stimulating nature of the work, has often resulted in carelessness and thus incorrect mounting of the pattern layer. The spatula may also cause scratches and even tears in the pattern layer or the stretch-fabric.
To facilitate application a lubricant, e.g. water, is generally used on the support means so that less friction is obtained between spatula and transfer film during the spatula work. A serious problem that may then arise is the formation of bubbles or blisters between the pattern layer and the stretch-fabric, caused by water or air becoming trapped between them. A hole must be made in the pattern layer to remove these blisters, allowing the enclosed liquid or air to be pressed out manually. Even if application of the pattern is performed most carefully, a few blisters containing moisture may still remain. When the sign is subsequently hung and is heated by the sun, the moisture enclosed is converted to water vapour and the bubbles gradually cause the adhesive agent to release its adhesion to the stretch-fabric, resulting in an ugly, uneven surface and a shorter service life for the sign. Furthermore, the present application method requires two people, one to apply the pattern with the spatula while the other holds the foil in position. For a sign with an area of 16 m2 the total time required for the method described is estimated at about 8 hours, i.e. 4 hours per man for a work team comprising two fitters.
In another known method of applying pattern layers on stretch-fabric, an application reel-up is used where the layers are passed in together, one on top of the other, through a nip between two rubber-clad press rolls, thereby effecting adhesion between the necessary layers. However, placing the pattern layer in the press nip so that it is always correctly positioned in relation to the stretch-fabric beneath during the adhesion process is extremely complicated since the adhesive layer is exposed. Even a minute error is sufficient to cause serious lateral displacement after only a few meters of the sign-matter has passed through the press nip. This is particularly so when more than one panel of pattern layer is to be applied next to or on top of another. There is thus currently no real chance of quickly, reliably and cost-efficiently producing stretch-fabric signs with a pattern which is both detailed and in several colours.
The application reel-up described above cannot be used when working with backings for large signs since it does not allow application of pattern layers on backings larger than the width of the press rolls in the reel-up. The width of the signs is thus limited to only about 1200 mm which is the width of the rolls normally used. However, foil cutters now available can manage a foil width of up to 1372 mm and since for marketing reasons it is desirable to manufacture larger stretch-fabric signs by combining several panels of pattern layer, the reel-up method is now out of date.
The principal object of the present invention is to provide an improved method and device for applying pattern layers onto a support means for a sign so that the problems mentioned above are entirely, or at least almost entirely eliminated.
A second object of the invention is to provide a method and a device for applying pattern layers on stretch-fabric considerably wider than the application rolls now available, and at the same time enabling application of several parallel pattern layers of currently maximum width panel by panel on one and the same large support means.
A third object of the invention is to provide a method and a device that makes pattern application simpler and quicker and requires less work than hitherto in the form of time and personal.
Another object of the invention is to provide a method and a device with which the manual assembly work using hand tools such as spatulas, and lubricant, and also the damage and inconvenience often caused by said hand tools and lubricants, are greatly reduced or even completely eliminated.
The method according to the invention is characterized in that a traverse spanning the laying-out surface in the application device is passed in controlled manner over the foil placed on the laminating table, that a self-adhesive transfer film supplied from a roll over and around at least one press roll rotatably journalled at its ends and supported by a press device arranged on said traverse, is applied under pressure on the foil to produce a first laminate consisting of transfer film and foil, that said carrier layer and spill of the pattern layer are removed either together or separately, that the pattern parts thus remaining on the transfer film, adhered to its self-adhesive surface, are thereafter brought into contact with the support means on the laying-out surface with the adhesive layer of the pattern parts now exposed, that the press roll of the traverse is again passed under pressure over the second laminate thus formed, consisting of transfer film, said pattern parts and support means so that the pattern parts are transferred permanently to said support means, that during said application the press roll will be caused to press out air enclosed in the second laminate, and that the transfer film is removed from the support means.
The device according to the invention is characterized in that it comprises a traverse spanning the laying-out surface, having linearly movable devices comprising control and journalling means, said devices travelling along fixed control and carrier sections running parallel to each other along each long side of the laminating table; and a press device comprising at least one press roll rotatably journalled at its ends and operating and control means for moving the press roll between an upper inoperative position and a lower operative position in contact with the surface of the table and for controlling the pressure of the press roll against the table surface.
A saving in time of up to 75% is achieved with the present invention compared with previously known methods. Using the present invention several parallel patterns can also be simply and efficiently applied onto the support means for stretch-fabric signs that are considerably larger than the width of the press rolls currently available, since in this case the foil is placed panel by panel on the surface of the application table, after which the adjacent panels can easily be accurately fitted together before the pattern layers from said foils are fixed to the stretch-fabric with the aid of transfer film and said press roll.
Additional advantages obtained by the present invention are that lubricant such as water is no longer necessary between the pattern layer and the spatula during application, and that the material used is not damaged by scraping of the spatula or by water remaining between the pattern layer and the stretch-fabric. The work can be performed more quickly since one end of the transfer film with the ready-cut pattern thereon can be secured to the support means with the aid of the press roll. The carrier layer is then removed so that the adhesive layer is exposed and application on the stretch-fabric can be performed while the traverse with the press roll is passed over the table, thereby producing perfect adhesion of the pattern layer.